We investigated the fluorescence emission from three fluorophores commonly used for labeling cells in flow cytometry. We have demonstrated that the fluorescence emission from cells labeled with fluorescein-isothiocyanate (FITC), phycoerythrin (PE), and allophycocyanin (APC) is considerably saturated and bleached in standard flow cytometric conditions. Therefore, for optimization of fluorescence...

The effect of excitation and emission wavelengths on fluorescence decay times of Chlorophyll a were measured in four solutions (C approximately 10(-5) mol X 1(-1] and in polymethyl methacrylate films. The decay times observed were corrected with respect to self-absorption and re-emission effects. The fluorescence decay times of Chlorophyll a was found to depend on both the excitation and the em...

     A simple, rapid, selective and highly sensitive fluorimetric method for determination of two catecholamines, i.e. norepinephrine (NE) and epinephrine (EP), in serum samples was developed. The method is based on the fluorescence sensitization of terbium (Tb3+) by complexation with both catecholamines in the presence of lanthanum (La3+), as a co-cation, and in a Na...

A simple method to determine fluorescence emission spectra of proteins in solid state is described. The available commercial accessories can only accommodate solid samples and hence do not allow a direct comparison between fluorescence spectra of a sample in solution and solid state form. Such comparisons are valuable to monitor the changes in protein structure when it is “dried” or immobilized...

The development of a dual probe that provides ratiometric measurements of fluid viscosity is described. The design is based on coupling of a primary fluorophore with viscosity-independent fluorescence emission (blue unit) with a secondary fluorophore that exhibits viscosity-sensitive fluorescent emission quantum yield (red unit). Excitation of the secondary fluorophore can be achieved via Reson...

A validated HPLC method was developed to determine doxorubicin concentration in a small volume of rat plasma (60 µl) with convenient fluorescence detection. Sample preparation includes a simple one-step liquid-liquid extraction using minimum amount of organic solvent, with extraction recoveries more than 95%. The analysis was accomplished using PerfectSil C18 column maintained at 35 °C and a mo...

A new sensitive, simple and rapid method for determination of methotrexate (MTX) was developed based on quenching effects of MTX on the fluorescence intensity of Tb3+-1,10-phenanthroline complex. The fluorescence intensity was measured with excitation wavelength of 300 nm and emission wavelength of 545 nm and the quenched fluorescence intensity is proportional to the concentration of MTX in Tris...

The group of 2D materials contains almost all the elements of the periodic table. In contrast to the graphene sheet, they are abundant, this creates a variety of electronic properties including metals, semimetals, insulators and semiconductors. Band gaps of these materials are direct or indirect by ranging from ultraviolet to infrared, for this reason, have received much attention for nanoelect...

In this article, we describe a photosensitizer (PS) whose ability to generate singlet oxygen (1O2) and fluorescence emission has been designed as tumor responsive. More specifically, the PS consists of a silicon phthalocyanine (SiPc) core, axially substituted with two subphthalocyanine (SubPc) units, covalently linked by a disulfide linker, which is cleavable in the presence of a strong reducin...

The interactions of β-lactoglobulin AB in the presence of cationic surfactants such as Cetyltrimethylammonium bromide and Cetyltrimethylammonium p-Toluenesulfonate have been investigated using a variety of experimental techniques such as conductivity, UV-Vis spectrophotometry and fluorimetry. The conductivity of surfactants aqueous solutions with β-lactoglobulin shows that the cmc of cationic s...